DOCSLIB.ORG

Fractal Branching Organizations of Ediacaran Rangeomorph Fronds Reveal a Lost Proterozoic Body Plan

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fractal Branching Organizations of Ediacaran Rangeomorph Fronds Reveal a Lost Proterozoic Body Plan Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan Jennifer F. Hoyal Cuthill1 and Simon Conway Morris Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom Edited by Andrew H. Knoll, Harvard University, Cambridge, MA, and approved June 17, 2014 (received for review May 8, 2014) The branching morphology of Ediacaran rangeomorph fronds has morphology than was previously possible. These parameters are no exact counterpart in other complex macroorganisms. As such, then used to reconstruct 3D space-filling strategies within the these fossils pose major questions as to growth patterns, func- group and evaluate potential frond functions, revealing an tional morphology, modes of feeding, and adaptive optimality. adaptive radiation of fractal organizations. This provides a new Here, using parametric Lindenmayer systems, a formal model of framework for the study of growth, functional morphology, rangeomorph morphologies reveals a fractal body plan character- and evolution of these lost constructions. ized by self-similar, axial, apical, alternate branching. Consequent morphological reconstruction for 11 taxa demonstrates an adap- Results and Discussion tive radiation based on 3D space-filling strategies. The fractal body Our L-system model comprises an initial axiom (starting plan of rangeomorphs is shown to maximize surface area, consis- branch segment), production rules for axial, apical, and alternate tent with diffusive nutrient uptake from the water column (osmo- branching; and 28 parameters which together control branch trophy). The enigmas of rangeomorph morphology, evolution, and production, elongation rates, and 3D branching angles (SI Ap- extinction are resolved by the realization that they were adaptively pendix, Table S1). This incorporates both (sub) apical branch optimized for unique ecological and geochemical conditions in the production (distal extremities form the sites for subsequent late Proterozoic. Changes in ocean conditions associated with the branching) and expansion (branches grow in length and diameter Cambrian explosion sealed their fate. throughout life), based on relative branch sizes and potential ontogenetic series (4, 6, 7, 20, 21). At each step in the axial paleobiology | paleontology branching process, an apical branch segment (e.g., the tip of the stem) produces one lateral branch segment (e.g., the beginning n parallel with large-scale geochemical transitions associated of a new primary lateral branch) and an additional axis segment – – Iwith ocean oxygenation (1 3), the Ediacaran Period (635 541 (e.g., the new stem apex) (Fig. 1, SI Appendix, and Movies S1– Ma) records a major diversification of multicellular eukaryotes. S3). Lateral branches are produced alternately (e.g., left then – Rangeomorph fronds (575 541 Ma) dominated early Ediacaran right) along a branch axis. Reconstruction of overall morpholo- biotas (4) and have a characteristic branching morphology, dis- gies that closely match the anatomy of the fossils (Fig. 2 and tinct from any known Phanerozoic organism (5). Although the SI Appendix) validates this model of branching and growth. fronds are often preserved as flattened impressions, exceptional Collectively, these reconstructions demonstrate how different moldic fossils preserve details of the 3D branching structure to body shapes and symmetry patterns [characteristics relied upon a resolution of 30 μm (6). Qualitative classifications for rangeo- morph branching patterns have been proposed (7, 8), but no Significance quantitative model has previously been formulated. Because branching is repeated over decreasing size scales (with up to four Rangeomorph fronds characterize the late Ediacaran Period observed orders of branching), rangeomorph fronds have been – informally described as self-similar and fractal (4–6). Although (575 541 Ma), representing some of the earliest large organ- this has potential implications for the functional optimality of their isms. As such, they offer key insights into the early evolution of multicellular eukaryotes. However, their extraordinary branch- morphologies (5, 9), the extent to which they are formally fractal ing morphology differs from all other organisms and has proved and self-similar (10, 11) has not previously been tested. Further- highly enigmatic. Here we provide a unified mathematical model more, until now, evolutionary transitions in branching patterns of rangeomorph branching, allowing us to reconstruct 3D have not been characterized within any quantitative framework. morphologies of 11 taxa and measure their functional proper- Rangeomorphs inhabited shallow to abyssal marine environ- – ties. This reveals an adaptive radiation of fractal morphologies ments (1, 8, 12 14), evidently precluding photosynthesis for most which maximized body surface area, consistent with diffusive taxa (12). Preservational features, including bending and over- nutrient uptake (osmotrophy). Rangeomorphs were adap- folding (4, 15), suggest that rangeomorphs were soft-bodied. No tively optimal for the low-competition, high-nutrient con- evidence exists for either motility or active feeding (such as ditions of Ediacaran oceans. With the Cambrian explosion in musculature, filter feeding organs, or a mouth). Consequently, animal diversity (from 541 Ma), fundamental changes in eco- rangeomorphs have been reconstructed as sessile, feeding on logical and geochemical conditions led to their extinction. organic carbon by diffusion (or possibly endocytosis) through the body surface (3, 5, 12, 16), with a large surface area to volume Author contributions: J.F.H.C. designed research; J.F.H.C. performed research; J.F.H.C. ratio aiding nutrient uptake (5, 16). The adaptive potential analyzed data; and J.F.H.C. and S.C.M. wrote the paper. of their different branching morphologies has, however, never The authors declare no conflict of interest. been quantified. This article is a PNAS Direct Submission. Here, using parametric Lindenmayer systems (L-systems) (17, See Commentary on page 12962. 18), we present a unified model to describe the branching 1To whom correspondence should be addressed. Email: [email protected]. structure of Ediacaran rangeomorph fronds. Our quantitative This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. parameters provide a far more detailed definition of frond 1073/pnas.1408542111/-/DCSupplemental. 13122–13126 | PNAS | September 9, 2014 | vol. 111 | no. 36 www.pnas.org/cgi/doi/10.1073/pnas.1408542111 Downloaded by guest on September 28, 2021 due to alternate branching on the right and left of an axis (7)], bilateral or tetraradial symmetry in apical view, and helical tor- SEE COMMENTARY sion around the main body axis (Fig. 3 and SI Appendix). Previous descriptions (following ref. 6) informally suggested that rangeomorphs possessed a shared fractal module consisting of a centimeter-scale, self-similar frondlet (conceptually similar to the primary lateral branch and associated subbranches, as formalized here). We demonstrate that rangeomorph morphologies can be re- constructed by applying approximately self-similar branch pro- duction rules (as described above) at increasingly fine scales, although these may be modified by different parameter values to give subtle variations in the level of self-similarity (SI Appendix,TableS1). These production rules apply across the branching system of the frond [sometimes called the petalodium (8)], from the stem (the 0-order branch, which produces the first-order lateral branches) to the highest order of branching (that is, from the third-order branches) (Fig. 1). This reveals that self-similarity extends beyond the frondlet, previously hypothesized to represent the basic modular unit (6). That is to say, the entire rangeomorph frond shows approximately self- similar branching, whereas the basic unit repeated throughout the frond is a cylindrical branch segment. This branch segment can be broadly related (6) to Seilacher’s concept of the fractal pneu (24). We also show that rangeomorph fronds are approximately fractal (10) with noninteger fractal dimensions of 1.6–2.4 as determined Fig. 1. Schematic L-system model of Beothukis mistakensis.(A) First three steps of the branching process. (B) Final morphology at step 38. Segment colors in- by the 3D box counting method (SI Appendix,Fig.S13). dicate relative age, from oldest (red) to youngest (light blue). Numbers indicate Shared possession of an approximately self-similar and fractal, branch order (0, stem; 1, primary; 2, secondary; 3, tertiary; and 4, quaternary). axial, apical, and alternate branching body plan supports a ran- geomorph clade (Rangeomorpha, Pflug, 1972, cited in ref. 8) but significantly increases the range of diagnostic characters [pre- by some previous comparative studies (22, 23)] emerge from viously restricted to repeated fine-scale branching (8) only visible variations on a shared branching pattern. Resulting body or- in exceptionally preserved specimens]. Note that this rangeo- ganizations include alternate-symmetry (also known as glide- morph body plan does not extend to other enigmatic Ediacaran symmetry) in frontal view [superficially bilateral symmetry, offset macroorganisms, such as Swartpuntia, Ernietta (8), or Dickinsonia EVOLUTION Fig. 2. Ediacaran rangeomorph fossils and their 3D L-system models. (A and B) Avalofractus abaculus. A reproduced with permission from ref. 4, figure 3.1. (C and D) Charnia masoni.(C) South
Load more

Recommended publications
  • Lessons from the Fossil Record: the Ediacaran Radiation, the Cambrian Radiation, and the End-Permian Mass Extinction
    OUP CORRECTED PROOF – FINAL, 06/21/12, SPi CHAPTER 5 Lessons from the fossil record: the Ediacaran radiation, the Cambrian radiation, and the end-Permian mass extinction S tephen Q . D ornbos, M atthew E . C lapham, M argaret L . F raiser, and M arc L afl amme 5.1 Introduction and altering substrate consistency ( Thayer 1979 ; Seilacher and Pfl üger 1994 ). In addition, burrowing Ecologists studying modern communities and eco- organisms play a crucial role in modifying decom- systems are well aware of the relationship between position and enhancing nutrient cycling ( Solan et al. biodiversity and aspects of ecosystem functioning 2008 ). such as productivity (e.g. Tilman 1982 ; Rosenzweig Increased species richness often enhances ecosys- and Abramsky 1993 ; Mittelbach et al. 2001 ; Chase tem functioning, but a simple increase in diversity and Leibold 2002 ; Worm et al. 2002 ), but the pre- may not be the actual underlying driving mecha- dominant directionality of that relationship, nism; instead an increase in functional diversity, the whether biodiversity is a consequence of productiv- number of ecological roles present in a community, ity or vice versa, is a matter of debate ( Aarssen 1997 ; may be the proximal cause of enhanced functioning Tilman et al. 1997 ; Worm and Duffy 2003 ; van ( Tilman et al. 1997 ; Naeem 2002 ; Petchey and Gaston, Ruijven and Berendse 2005 ). Increased species rich- 2002 ). The relationship between species richness ness could result in increased productivity through (diversity) and functional diversity has important 1) interspecies facilitation and complementary implications for ecosystem functioning during resource use, 2) sampling effects such as a greater times of diversity loss, such as mass extinctions, chance of including a highly productive species in a because species with overlapping ecological roles diverse assemblage, or 3) a combination of biologi- can provide functional redundancy to maintain cal and stochastic factors ( Tilman et al.
    [Show full text]
  • RELATING EDIACARAN FRONDS 1 T. Alexander Dececchi *, Guy M
    1 RELATING EDIACARAN FRONDS 2 T. Alexander Dececchi *, Guy M. Narbonne, Carolyn Greentree, and Marc 3 Laflamme 4 T. Alexander Dececchi* and Guy M. Narbonne, Department of Geological Sciences 5 and Geological Engineering, Kingston, Queen's University, Ontario, K7L 3N6, Canada. 6 E-mail: [email protected], [email protected]. 7 Carolyn Greentree, School of Earth, Atmosphere and Environment, Monash 8 University, Clayton, Victoria, 3800, Australia. Email [email protected]. 9 Marc Laflamme. Department of Chemical and Physical Sciences, University of 10 Toronto, Mississauga, 3359 Mississauga Road, Mississauga, Ontario, L5L 1C6, 11 Canada. E-mail: [email protected]. 12 13 Abstract 14 Ediacaran fronds are key components of terminal-Proterozoic ecosystems. They 15 represent one of the most widespread and common body forms ranging across all 16 major Ediacaran fossil localities and time slices postdating the Gaskiers glaciation, 17 but uncertainty over their phylogenetic affinities has led to uncertainty over issues 18 of homology and functional morphology between, and within, organisms displaying 19 this ecomorphology. Here we present the first large scale, multi-group cladistic 20 analysis of Ediacaran organisms, sampling 20 ingroup taxa with previously asserted 21 affinities to the Arboreomorpha, Erniettomorpha and Rangeomorpha. Using a newly 22 derived morphological character matrix that incorporates multiple axes of potential 23 phylogenetically informative data, including architectural, developmental, and 24 structural qualities, we seek to illuminate the evolutionary history of these 25 organisms. We find strong support for existing classification schema and devise 26 apomorphy-based definitions for each of the three frondose clades examined here. 27 Through a rigorous cladistics framework it is possible to discern the pattern of 28 evolution within, and between, these clades, including the identification of 29 homoplasies and functional constraints.
    [Show full text]
  • Rangeomorph Classification Schemes and Intra-Specific Variation: Are All
    Downloaded from http://sp.lyellcollection.org/ by guest on September 23, 2021 Rangeomorph classification schemes and intra-specific variation: are all characters created equal? CHARLOTTE G. KENCHINGTON1,2* & PHILIP R. WILBY3 1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK 2Present address: Department of Earth Sciences, Memorial University of Newfoundland, Prince Philip Drive, St John’s, NL, A1B 3X5, Canada 3British Geological Survey, Environmental Science Centre, Nicker Hill, Keyworth, Nottingham NG12 5GG, UK *Correspondence: [email protected] Abstract: Rangeomorphs from the Ediacaran of Avalonia are among the oldest known complex macrofossils and our understanding of their ecology, ontogeny and phylogenetic relationships relies on accurate and consistent classification. There are a number of disparate classification schemes for this group, which dominantly rely on a combination of their branching characters and shape metrics. Using multivariate statistical analyses and the diverse stemmed, multifoliate rangeomorphs in Charnwood Forest (UK), we assess the taxonomic usefulness of the suite of char- acters currently in use. These techniques allow us to successfully discriminate taxonomic groupings without a priori assumptions or weighting of characters and to document a hitherto unrecognized level of variation within single taxonomic groups. Variation within the currently defined genus Pri- mocandelabrum is too great to be realistically assigned to different species and may instead reflect primary character diversity, ontogenetic changes in character state or ecophenotypic variability. Its recognition cautions against generic-level diagnoses based on single differences in character state and will be crucial in understanding the mode of growth of these enigmatic organisms. Supplementary material: Data tables, definition of the characters used in the analyses, and detailed descriptions and breakdowns of methods and results are available at https://doi.org/10.
    [Show full text]
  • Fossils, Feeding, and the Evolution of Complex Multicellularity
    Fossils, Feeding, and the Evolution of Complex Multicellularity The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Knoll, Andrew H., and Daniel J.G. Lahr. 2016. "Fossils, feeding, and the evolution of complex multicellularity." In Multicellularity, Origins and Evolution, The Vienna Series in Theoretical Biology, eds. Karl J. Niklas and Stuart A. Newman. Cambridge, MA: MIT Press. Published Version https://mitpress.mit.edu/books/multicellularity Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:34390340 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#OAP Fossils, Feeding, and the Evolution of Complex Multicellularity Andrew H. Knoll and Daniel J. G. Lahr Andrew H. Knoll Department of Organismic and Evolutionary Biology, Harvard University Daniel J.G. Lahr Department of Zoology, Institute of Biosciences, University of São Paulo The evolution of complex multicellularity is commonly viewed as a series of genomic events with developmental consequences. It is surely that, but a focus on feeding encourages us to view it, as well, in terms of functional events with ecological consequences. And fossils remind us that these events are also historical, with environmental constraints and consequences. Several definitions of complex multicelluarity are possible; here we adopt to view that complex multicellular organisms are those with tissues or organs that permit bulk nutrient and gas transport, thereby circumventing the limitations of diffusion (Knoll, 2011).
    [Show full text]
  • PERSATUAN GEOLOGI MALAYSIA WARTA GEOLOGI NEWSLETTER of the GEOLOGICAL SOCIETY of MALAYSIA
    PERSATUAN GEOLOGI MALAYSIA WARTA GEOLOGI NEWSLETTER of the GEOLOGICAL SOCIETY OF MALAYSIA 50TH ANNIVERSARY SPECIAL ISSUE Jilid 43 OCTOBER – DECEMBER Volume 43 No. 4 2017 No. 4 ISSN 0126 - 5539 PP2509/07/2013(032786) Warta Geologi Newsletter of the Geological Society of Malaysia PERSATUAN GEOLOGI MALAYSIA Editor Geological Society of Malaysia Wan Hasiah Abdullah (University of Malaya) Council 2017/2018 Editorial Board President : Mr. Abd. Rasid Jaapar Chow Weng Sum Vice President : Dr. Che Aziz Ali Universiti Teknologi Petronas, Malaysia Secretary : Mr. Lim Choun Sian Azman A. Ghani Assistant Secretary : Mr. Askury Abd Kadir University of Malaya, Malaysia Treasurer : Mr. Ahmad Nizam Hasan Harry Doust Editor : Prof. Dr. Wan Hasiah Abdullah The Netherlands & Vrije Universiteit, Immediate Past President : Dr. Mazlan Madon Amsterdam Councillors : Ms. Marelyn Telun Daniel Robert Hall Dr. Meor Hakif Amir Hassan University of London, UK Mr. Muhammad Ashahadi Dzulkafli Dr. Norbet Simon Howard Johnson Imperial College London, UK Mr. Nicholas Jacob Dr. Nur Iskandar Taib Ibrahim Komoo Mr. Tan Boon Kong Universiti Kebangsaan Malaysia, Malaysia Dato’ Yunus Abdul Razak Alfredo Lagmay University of the Philippine, Philippine Lee Chai Peng University of Malaya, Malaysia The Geological Society of Malaysia was founded in Mohd Shafeea Leman 1967 with the aim of promoting the advancement of Universiti Kebangsaan Malaysia, Malaysia geoscience, particularly in Malaysia and Southeast Asia. The Society has a membership of about 600 Ian Metcalfe local and international geoscientists. University of New England, Australia Ng Tham Fatt Warta Geologi (Newsletter of the Geological University of Malaya, Malaysia Society of Malaysia) is published quarterly by the Society. Warta Geologi covers short geological Peter R.
    [Show full text]
  • Annual Meeting 2011
    The Palaeontological Association 55th Annual Meeting 17th–20th December 2011 Plymouth University PROGRAMME and ABSTRACTS Palaeontological Association 2 ANNUAL MEETING ANNUAL MEETING Palaeontological Association 1 The Palaeontological Association 55th Annual Meeting 17th–20th December 2011 School of Geography, Earth and Environmental Sciences, Plymouth University The programme and abstracts for the 55th Annual Meeting of the Palaeontological Association are outlined after the following summary of the meeting. Venue The meeting will take place on the campus of Plymouth University. Directions to the University and a campus map can be found at <http://www.plymouth.ac.uk/location>. The opening symposium and the main oral sessions will be held in the Sherwell Centre, located on North Hill, on the east side of campus. Accommodation Delegates need to make their own arrangements for accommodation. Plymouth has a large number of hotels, guesthouses and hostels at a variety of prices, most of which are within ~1km of the University campus (hotels with PL1 or PL4 postcodes are closest). More information on these can be found through the usual channels, and a useful starting point is the website <http://www.visitplymouth.co.uk/site/where-to-stay>. In addition, we have organised discount rates at the Jury’s Inn, Exeter Street, which is located ~500m from the conference venue. A maximum of 100 rooms have been reserved, and will be allocated on a first-come-first-served basis. Further information can be found on the Association’s website. Travel Transport into Plymouth can be achieved via a variety of means. Travel by train from London Paddington to Plymouth takes between three and four hours depending on the time of day and the number of stops.
    [Show full text]
  • Rangeomorph Classification Schemes and Intra-Specific Variation: Are All
    Downloaded from http://sp.lyellcollection.org/ by guest on October 1, 2021 Rangeomorph classification schemes and intra-specific variation: are all characters created equal? CHARLOTTE G. KENCHINGTON1,2* & PHILIP R. WILBY3 1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK 2Present address: Department of Earth Sciences, Memorial University of Newfoundland, Prince Philip Drive, St John’s, NL, A1B 3X5, Canada 3British Geological Survey, Environmental Science Centre, Nicker Hill, Keyworth, Nottingham NG12 5GG, UK *Correspondence: [email protected] Abstract: Rangeomorphs from the Ediacaran of Avalonia are among the oldest known complex macrofossils and our understanding of their ecology, ontogeny and phylogenetic relationships relies on accurate and consistent classification. There are a number of disparate classification schemes for this group, which dominantly rely on a combination of their branching characters and shape metrics. Using multivariate statistical analyses and the diverse stemmed, multifoliate rangeomorphs in Charnwood Forest (UK), we assess the taxonomic usefulness of the suite of char- acters currently in use. These techniques allow us to successfully discriminate taxonomic groupings without a priori assumptions or weighting of characters and to document a hitherto unrecognized level of variation within single taxonomic groups. Variation within the currently defined genus Pri- mocandelabrum is too great to be realistically assigned to different species and may instead reflect primary character diversity, ontogenetic changes in character state or ecophenotypic variability. Its recognition cautions against generic-level diagnoses based on single differences in character state and will be crucial in understanding the mode of growth of these enigmatic organisms. Supplementary material: Data tables, definition of the characters used in the analyses, and detailed descriptions and breakdowns of methods and results are available at https://doi.org/10.
    [Show full text]
  • Ediacaran Extinction and Cambrian Explosion
    Opinion Ediacaran Extinction and Cambrian Explosion 1, 2 3 4 Simon A.F. Darroch, * Emily F. Smith, Marc Laflamme, and Douglas H. Erwin The Ediacaran–Cambrian (E–C) transition marks the most important geobio- Highlights logical revolution of the past billion years, including the Earth’s first crisis of We provide evidence for a two-phased biotic turnover event during the macroscopic eukaryotic life, and its most spectacular evolutionary diversifica- Ediacaran–Cambrian transition (about tion. Here, we describe competing models for late Ediacaran extinction, 550–539 Ma), which both comprises the Earth’s first major biotic crisis of summarize evidence for these models, and outline key questions which will macroscopic eukaryotic life (the disap- drive research on this interval. We argue that the paleontological data suggest pearance of the enigmatic ‘Ediacara – – two pulses of extinction one at the White Sea Nama transition, which ushers biota’) and immediately precedes the Cambrian explosion. in a recognizably metazoan fauna (the ‘Wormworld’), and a second pulse at the – E C boundary itself. We argue that this latest Ediacaran fauna has more in Wesummarizetwocompetingmodelsfor – common with the Cambrian than the earlier Ediacaran, and thus may represent the turnover pulses an abiotically driven model(catastrophe)analogoustothe‘Big the earliest phase of the Cambrian Explosion. 5’ Phanerozoic mass extinction events, and a biotically driven model (biotic repla- Evolutionary and Geobiological Revolution in the Ediacaran cement) suggesting that the evolution of The late Neoproterozoic Ediacara biota (about 570–539? Ma) are an enigmatic group of soft- bilaterian metazoans and ecosystem engineering were responsible. bodied organisms that represent the first radiation of large, structurally complex multicellular eukaryotes.
    [Show full text]
  • Rangeomorphs, Thectardis (Porifera?) and Dissolved Organic Carbon in the Ediacaran Oceans E
    Geobiology (2011), 9, 24–33 DOI: 10.1111/j.1472-4669.2010.00259.x Rangeomorphs, Thectardis (Porifera?) and dissolved organic carbon in the Ediacaran oceans E. A. SPERLING,1,2 K. J. PETERSON3 AND M. LAFLAMME1 1Department of Geology and Geophysics, Yale University, New Haven, CT, USA 2Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA 3Department of Biological Sciences, Dartmouth College, Hanover, NH, USA ABSTRACT The mid-Ediacaran Mistaken Point biota of Newfoundland represents the first morphologically complex organ- isms in the fossil record. At the classic Mistaken Point localities the biota is dominated by the enigmatic group of ‘‘fractally’’ branching organisms called rangeomorphs. One of the few exceptions to the rangeomorph body plan is the fossil Thectardis avalonensis, which has been reconstructed as an upright, open cone with its apex in the sediment. No biological affinity has been suggested for this fossil, but here we show that its body plan is consis- tent with the hydrodynamics of the sponge water-canal system. Further, given the habitat of Thectardis beneath the photic zone, and the apparent absence of an archenteron, movement, or a fractally designed body plan, we suggest that it is a sponge. The recognition of sponges in the Mistaken Point biota provides some of the earliest body fossil evidence for this group, which must have ranged through the Ediacaran based on biomarkers, molec- ular clocks, and their position on the metazoan tree of life, in spite of their sparse macroscopic fossil record. Should our interpretation be correct, it would imply that the paleoecology of the Mistaken Point biota was domi- nated by sponges and rangeomorphs, organisms that are either known or hypothesized to feed in large part on dissolved organic carbon (DOC).
    [Show full text]
  • Mistaken Point, with Insets Showing Some of the Diverse Ediacaran Macrofossils Present at Mistake Point (Photo: A
    Open File NFLD/3320 GEOLOGICAL ASSOCIATION OF CANADA Newfoundland and Labrador Section 2015 FALL FIELD TRIP The Ediacaran fossils of the Avalon Peninsula Alex G. Liu and James Conliffe with contributions from Liam Herringshaw, Jack Matthews, and Duncan McIlroy September 18–20th, 2015 Cover photo: Overview of the fossil bearing bedding planes at Mistaken Point, with insets showing some of the diverse Ediacaran macrofossils present at Mistake Point (photo: A. Liu) GAC Newfoundland and Labrador Section – 2015 Fall Field Trip Ediacaran macrofossils from the Mistaken Point ‘E’ Surface. 2 GAC Newfoundland and Labrador Section – 2015 Fall Field Trip TABLE OF CONTENTS INTRODUCTION AND OVERVIEW 4 ACKNOWLEDGEMENTS 4 SAFETY INFORMATION 5 MISTAKEN POINT ECOLOGICAL RESERVE (MPER) 7 PART 1: BACKGROUND MATERIAL 9 INTRODUCTION 9 Introduction to the Neoproterozoic‒Phanerozoic Transition 9 Stratigraphy, Structural Geology, and Depositional Environment of the Avalon Peninsula 13 EDICARAN PALEONTOLOGY OF THE AVALON PENINSULA 16 Preservation of Ediacaran macrofossils 16 The Avalon Assemblage 18 Current research into the Mistaken Point Ediacaran Fossils 21 PART 2: FIELD TRIP ITINERARY 24 Day One – Harbour Main and Spaniard’s Bay 25 Day Two – Mistaken Point Ecological Reserve 31 Day Three – Mistaken Point Ecological Reserve and Ferryland 46 INVENTORY OF TAXA IN MISTAKEN POINT ECOLOGICAL RESERVE 53 REFERENCES 54 3 GAC Newfoundland and Labrador Section – 2015 Fall Field Trip INTRODUCTION AND OVERVIEW The Mistaken Point Ecological Reserve (Fig. 1) is home to the some of the world’s most impressive Ediacaran fossil assemblages. Large bedding planes covered in thousands of exceptionally preserved specimens can be found in situ throughout a continuous ~2 km succession of sedimentary strata.
    [Show full text]
  • SERIES Ontogeny, Taphonomy, Taxonomy and Morphology, Offering Insights Into the Possible Phylogenetic Positions of Ediacaran Taxa Within the Tree of Life
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ESC Publications - Cambridge Univesity GEOSCIENCE CANADA Volume 44 2017 63 SERIES ontogeny, taphonomy, taxonomy and morphology, offering insights into the possible phylogenetic positions of Ediacaran taxa within the tree of life. Meanwhile, a thick and continuous geological record enables the fossils to be placed within a well- resolved temporal and paleoenvironmental context spanning an interval of at least 10 million years. This article reviews the history of paleontological research at MPER, and highlights key discoveries that have shaped global thinking on the Edi- acaran macrobiota. RÉSUMÉ Le site du Patrimoine mondial de la Réserve écologique de Mis- taken Point (MPER), sur la côte sud-est de Terre-Neuve, au Canada, est l'une des principales localités fossilifères édiacari- ennes de la planète. Le MPER renferme quelques-uns des plus anciens assemblages connus de macrobiote édicarien à parties Great Canadian Lagerstätten 6. molles, et ses fossiles ont contribué de manière significative à Mistaken Point Ecological Reserve, la recherche paléobiologique édiacarienne depuis leur décou- verte en 1967. La préservation de multiples paléocommu- Southeast Newfoundland nautés benthiques in situ, dont certaines comptant des milliers de spécimens, a permis de faire des recherches en paléoécolo- Alexander G. Liu1 and Jack J. Matthews2, 3 gie, ontogenèse, taphonomie, taxonomie et morphologie de biotes édiacariens, ce qui a permis d’avoir un aperçu de dif- 1Department of Earth Sciences férentes positions phylogénétiques possibles des taxons édi- University of Cambridge acariens dans l'arborescence biologique. Aussi, grâce à une Downing Street, Cambridge, CB2 3EQ, United Kingdom colonne géologique épaisse et continue, on a pu placer ces fos- E-mail: [email protected] siles dans un contexte temporel et paléoenvironnemental bien circonscrit qui s’étend sur un intervalle d'au moins 10 millions 2Department of Earth Sciences d'années.
    [Show full text]
  • Os Primeiros Momentos Da Vida Na Terra Como Os Primeiros 2 Bilhões De Anos De Evolução Biológica Traçaram O Destino Dos Seres Vivos?
    Os primeiros momentos da vida na Terra Como os primeiros 2 bilhões de anos de evolução biológica traçaram o destino dos seres vivos? Edição especial - Seção I EDITORIAL EDIÇÃO COMEMORATIVA Caros Leitores, É com imenso prazer que apresentamos a edição comemorativa de 10 anos do Boletim PETBio, uma longa caminhada contribuindo para a divulgação dos conhecimentos científicos à toda comunidade. Nessa edição prepare-se para fazer uma longa viagem pela história Ano 10 do Boletim PETBio UFMA da vida na Terra, uma vez que todos os artigos foram baseados no ciclo de seminários do PET Biologia, apresentado pelos petianos e intitulado “Os pontos cruciais da evolução da vida: reconstruindo realização do Boletim PETBio é uma atividade do grupo PET Biologia da Universidade Federal do Maranhão - a história da Terra”. Assim, essa edição está sendo dividida em Campus Dom Delgado (UFMA) presente desde seus primeiros anos de fundação. No entanto, possuía formato três partes, inicialmente temos “Os primeiros momentos da vida na Terra”, a segunda parte “A vida se diversifica em terra firme” e mais simples e sua divulgação não era feita de forma periódica. Após uma época de inatividade, o Boletim a terceira “A formação do mundo moderno”. Esperamos que essa SUMÁRIO Afoi reativado em 2007, adquirindo periodicidade trimestral, o que possibilitou a aquisição de seu ISSN 2237-6372 em fascinante viagem seja um portal para o conhecimento sobre a vida. 2010. Sua distribuição é gratuita e atualmente sua estrutura se dá por meio de seções fixas como Artigo Científico, Vamos juntos nessa jornada? Ensaios (antiga seção Resenhas), Escreva você também, Ponto de vista biológico, Notícias, Eventos, Linha de pesquisa Boa Leitura! e Entrevista, além de outras seções incluídas eventualmente, como: Monografias, Charges, Carta ao Leitor e PET na Mayara Ingrid Sousa Lima estrada.
    [Show full text]